We are concerned here, in particular, with so-called collision warning systems which warn a driver of a motor vehicle when a collision between a motor vehicle and the vehicle-external object is imminent. In order to warn the driver it is possible, for example, for an acoustic or a visual warning signal to be output. In this context, DE 10 2012 203 228 A1 describes a method for avoiding or for attenuating consequences in the case of collisions of a motor vehicle with an obstacle in a nearby region to the side of the motor vehicle. In the method, a driving tube of the motor vehicle is determined and a collision is determined on the basis of the driving tube of the motor vehicle and the position of the obstacle. In addition, when the risk of a collision is determined, a steering angle of rear wheels of the motor vehicle is set in such a way that the obstacle is avoided.
Furthermore, DE 101 28 792 A1 describes a system for avoiding collisions of a vehicle with obstacles. In this context, during the continuation of the journey in the next time periods the required driving space of the motor vehicle is calculated in advance and compared with the detected actual obstacle-free driving space which is present. This comparison provides an early prediction of a possible collision. The driver is alerted to the risk of collision by corresponding warning devices and can therefore react promptly. For example, a warning signal can be output if a predefined distance is undershot.
Furthermore, a warning device for motor vehicles is known from DE 198 43 564 A1. The warning device serves to monitor a distance of a vehicle from an obstacle and has a warning signal generator which is controlled by an evaluation and control device for generating a close-range warning signal if the distance estimated by the evaluation and control device is lower than a limiting value. Furthermore, there is provision that the evaluation and control device comprises means for estimating a collision of the vehicle with the obstacle on the basis of the estimated distance and the speed of the vehicle, and that the evaluation and control device controls the warning signal generator to output a long-range warning signal if the estimated distance is higher than the limiting value and the estimation reveals the presence of a risk of collision.
In addition, DE 10 2010 023 164 A1 describes a method for warning a driver of a motor vehicle about the presence of an object in the surroundings. In this context, a relative position of the object with respect to the motor vehicle and an anticipated driving path of the motor vehicle are determined. The driver is warned by a driver assistance system after a warning criterion is met, wherein in this context the actual length of the driving path between the motor vehicle and the object is taken into account. In this case, the driver is therefore warned only if it is actually necessary.